Stadium: Court 1 Round: 45 Ground: Clay
| ITF Spain F10 | 2018/04/24 08:00 | Niesten, Miliaan v Romero de Avila Senise, Alberto | 3-6,2-6 |
| ITF Portugal F8 | 2018/04/21 14:10 | Niesten, Miliaan v Cacao, Tiago | 4-6,5-7 |
| ITF Portugal F8 | 2018/04/20 10:00 | Niesten, Miliaan v Barry, Sam | 6-3,6-4 |
| ITF Portugal F8 | 2018/04/18 12:10 | Sao Thiago, Igor v Niesten, Miliaan | 1-6,3-6 |
| ITF Portugal F7 | 2018/04/12 12:20 | Niesten, Miliaan v Frederico Ferreira Silva | 0-6,5-7 |
| ITF Portugal F7 | 2018/04/11 09:00 | Prechtel, Sebastian v Niesten, Miliaan | 6-7,2-6 |
| ITF Portugal F7 Qual | 2018/04/09 10:00 | Niesten, Miliaan v Daniel Batista | 5-7,6-2,6-2 |
| ITF Portugal F7 Qual | 2018/04/08 16:00 | Niesten, Miliaan v Teixeira, Duarte Nuno | 6-3,6-3 |